Transrectal Ultrasound Probe Research Articles

A Novel Stereotactic Prostate Biopsy System Integrating Pre-Interventional Magnetic Resonance Imaging and Live Ultrasound Fusion

We developed an effective way to precisely diagnose prostate cancer using a novel prostate biopsy system that integrates pre-interventional magnetic resonance imaging with peri-interventional ultrasound for perineal navigated prostate biopsy. A total of 106 men with findings suspicious for prostate cancer (median age 66 years, prostate specific antigen 8.0 ng/ml and prostate volume 47 ml) underwent multiparametric 3 Tesla magnetic resonance imaging. Suspicious lesions were marked and data were transferred to the novel biopsy system. Using a custom-made biplane transrectal ultrasound probe mounted on a stepper we gathered 3-dimensional ultrasound data and fused them with magnetic resonance imaging data. As a result, suspicious magnetic resonance imaging lesions were superimposed over the transrectal ultrasound data. Three-dimensional biopsy planning was done, including systematic biopsies. Perineal biopsies were taken under live ultrasound guidance and the precise site of each biopsy was documented in 3 dimensions. We evaluated feasibility, safety and cancer detection. Prostate cancer was detected in 63 of 106 patients (59.4%). Magnetic resonance imaging findings correlated positively with histopathology in 71 of 103 patients (68.9%). In magnetic resonance imaging lesions marked as highly suspicious, the detection rate was 95.8% (23 of 24 cases). Lesion targeted cores had a significantly higher positivity rate than nontargeted cores. The procedural targeting error of the first 2,461 biopsy cores was 1.7 mm. Regarding adverse effects, 2 patients experienced urinary retention and 1 had a perineal hematoma. Urinary tract infections did not develop. Perineal stereotactic prostate biopsies guided by the combination of magnetic resonance imaging and ultrasound enable effective examination of suspicious magnetic resonance imaging lesions. Each biopsy core taken is documented accurately for its location in 3 dimensions, enabling magnetic resonance imaging validation and tailored treatment planning. The morbidity of the procedure was minimal.

Robotic Transperineal Prostate Biopsy: Pilot Clinical Study

To develope a robot (BioXbot) that performs mapping transperineal prostate biopsy (PB) with two perineal skin punctures under ultrasound guidance. Our pilot study's clinical endpoints were complications and its technical endpoints were the duration for each phase. This institution review board-approved prospective clinical trial included patients with indications for PB. Two urologists performed these PBs. In the lithotomy position and under general anesthesia, the transrectal biplane ultrasound probe acquired transverse images of the prostate gland. The urologist defined its boundaries and planned the biopsy. It guided the PB in 3 axes, passing through a single perineal skin puncture for each prostate side. After each biopsy, it automatically moved to the next position. The steps were repeated on the contralateral side. Our 20 patients had a mean prostate-specific antigen of 8.4 ± 4.9 ng/mL. Two patients had 2 previous biopsies, whereas the rest had one. The mean number of biopsies taken was 28.5 ± 6.2 in a mean total procedure time of 32.5 ± 3.2 minutes. We detected 3 patients with prostate cancer with Gleason score 3 + 3. Two patients required brief bladder catheterization after their biopsy. Their prostate volumes were >50 mL and the number of biopsies taken was >30 cores. There was no mechanical failure, sepsis, bleeding per-rectal, or perineal hematoma. This pilot study demonstrated BioXbot's safety and feasibility as a biopsy platform. It can potentially be used for image-guided PB and focal therapy.

Does the transrectal ultrasound probe influence prostate cancer detection in patients undergoing an extended prostate biopsy scheme? Results of a large retrospective study

• To compare the prostate cancer detection rate and tolerance profile between a transrectal biopsy made with a 'side fire' (SF) and an 'end fire' (EF) ultrasound probe. • We selected patients undergoing first biopsy and re-biopsy of the prostate with a 14- and 18-core template using EF and SF transrectal probes, respectively. • We compared the cancer detection rate between the two probes on first biopsy and re-biopsy and gauged patient tolerance using a visual analogue scale (VAS). • A total of 1705 patients were included in the first biopsy group, while 487 were in the re-biopsy group. • The overall detection rate of first biopsy was 37.2%; the overall detection rate of re-biopsy was 10.1%. • No significant difference was found between the two probes in the first biopsy and re-biopsy sets (38% vs 36.5%, P= 0.55; 10.8% vs 9.3%, P= 0.7). • The lack of any significant association between the type of probe used and prostate cancer detection was confirmed by univariable and multivariable analyses in both the first biopsy and re-biopsy sets after accounting for prostate-specific antigen values, per cent free prostate-specific antigen, digital rectal examination, and prostate and transition zone volumes. • The patient tolerance profile of the SF group was significantly better than that of the EF group (mean VAS 1.78 ± 2.01 vs 1.45 ± 2.21; P= 0.02). • The prostate cancer detection rate does not depend on the type of probe used. However, the SF transrectal probe is associated with a better patient tolerance profile.

Haptic Simulator for Prostate Brachytherapy with Simulated Needle and Probe Interaction

This paper presents a haptic simulator for prostate brachytherapy. Both needle insertion and the manipulation of the transrectal ultrasound (TRUS) probe are controlled via haptic devices. Tissue interaction forces that are computed by a deformable tissue model based on the finite element method (FEM) are rendered to the user by these devices. The needle insertion simulation employs 3D models of needle flexibility and asymmetric tip bevel. The needle-tissue simulation allows a trainee to practice needle insertion and targeting. The TRUS-tissue interaction simulation allows a trainee to practice the 3D intraoperative TRUS placement for registration with the preoperative volume study and to practice TRUS axial translation and rotation for imaging needles during insertions. Approaches to computational acceleration for realtime haptic performance are presented. Trade-offs between accuracy and speed are discussed. A graphics-card implementation of the numerically intensive mesh-adaptation operation is also presented. The simulator can be used for training, rehearsal, and treatment planning.

WE-G-220-03: Evaluating Image-Similarity Metrics to Detect Prostate Motion during 3D TRUS-Guided Prostate Biopsy

Purpose: For 3D transrectal ultrasound(TRUS) guided prostate biopsy, we evaluate the utility of image‐similarity metrics for comparing real‐time 2D‐ TRUS video frames to pre‐acquired 3D‐TRUS images in order to detect misalignment due to prostate motion and deformation. Methods: The experiments were conducted on retrospective data of 3D TRUSimages from 3 subjects at the start of the biopsy procedure using a mechanically assisted 3D TRUS‐guided biopsy system. For each subject, 2D TRUSimages were acquired immediately prior to biopsy needle insertion. In this work, simulation and real human studies were performed to explore the utility of two image similarity metrics (normalized cross correlation and mutual information) for the detection of prostate motion during the biopsy procedure. Rigid prostate motion was simulated by translating the 3D volume in the direction orthogonal to the ground truth image, and by rotating the 3D volume around the long axis of the TRUS probe. We calculated similarity metrics for each of these simulated motion images and its corresponding ground truth image. In the human study, we performed preliminary testing of a 2D‐to‐3D rigid intensity‐based registration method and measured its error by calculating its target registration error (TRE), based on identified anatomically homologous intrinsic fiducial pairs. Results: The registration gave an overall TRE of 2.1 mm, and both the mutual information and normalized cross correlation metrics have a convex shape near the optimal plane. Conclusions: The convex metric profiles encourage the use of intensity‐based registration to compensate for motion and deformation of the prostate during TRUS‐guided biopsy. The gradient of the mutual information curves are generally higher, making this metric more sensitive to the detection of small misalignments. The normalized cross correlation has a higher capture range, making it more suitable to be used in an image registration where the initialization may be less than ideal.

Modelling Prostate Motion for Data Fusion During Image-Guided Interventions

There is growing clinical demand for image registration techniques that allow multimodal data fusion for accurate targeting of needle biopsy and ablative prostate cancer treatments. However, during procedures where transrectal ultrasound (TRUS) guidance is used, substantial gland deformation can occur due to TRUS probe pressure. In this paper, the ability of a statistical shape/motion model, trained using finite element simulations, to predict and compensate for this source of motion is investigated. Three-dimensional ultrasound images acquired on five patient prostates, before and after TRUS-probe-induced deformation, were registered using a nonrigid, surface-based method, and the accuracy of different deformation models compared. Registration using a statistical motion model was found to outperform alternative elastic deformation methods in terms of accuracy and robustness, and required substantially fewer target surface points to achieve a successful registration. The mean final target registration error (based on anatomical landmarks) using this method was 1.8 mm. We conclude that a statistical model of prostate deformation provides an accurate, rapid and robust means of predicting prostate deformation from sparse surface data, and is therefore well-suited to a number of interventional applications where there is a need for deformation compensation.

Size of the transrectal ultrasound probe makes no difference in pain perception during TRUS-Bx under adequate local anesthesia

In the great majority of the cases, transrectal ultrasound guided prostate biopsy (TRUS-Bx) is the definitive step in the diagnosis of prostate cancer (CaP). Although this procedure is well tolerated by most patients, it can result in considerable discomfort that can effectively be overcome with local injection anesthesia. In this study, we evaluated the effect of the size (i.e., circumference) of the transrectal probe on pain during TRUS-Bx. One hundred and seventy eligible patients who had elevated total prostate specific antigen (tPSA) and/or abnormal digital rectal examination (DRE) were included in this study. Patients (pts.) were divided into three TRUS-Bx groups; Group I: 60 pts. underwent TRUS-Bx with newer B-K Type 8808 probe (circumference 58 mm) under injectable periprostatic anesthesia, Group II: 60 pts. underwent TRUS-Bx with B-K Type 8551 probe (circumference 74 mm) under injectable periprostatic anesthesia, and Group III: 50 pts. underwent TRUS-Bx with B-K Type 8551 probe (circumference 74 mm) without local anesthesia. Periprostatic injection anesthesia was performed with 10 cc, 1% lidocaine (5 cc on each side) 10 min before TRUS-Bx. Pain was assessed using a 10-point modified visual analog scale (VAS) 15 min after the biopsy procedure. Three groups were homogeneous with respect to age and tPSA, and no statistically significant difference was observed in terms of mean biopsy duration between the 3 groups. Most of the patients experienced no pain to slight pain in Groups I and II, but 66% of the patients had more than moderate pain (VAS ≥ 5) in Group III with mean VAS score statistically higher than the other two groups (Group I vs. III, P = 0.0001; Group II vs. III, P = 0.0001). Mean VAS score was not statistically different between Group I and II (P = 0.126). No statistically significant difference in VAS pain perception was observed between different age categories within the Group I, II, and III. In the absence of injectable local anesthesia, larger probe (74 mm) results in much higher VAS pain perception than same size and smaller (58 mm) probe used under injectable local anesthesia. However, under injectable local anesthesia, the size (circumference) of the transrectal probe (58 mm vs. 74 mm) does not result in any different pain perception during TRUS-Bx.

Development and validation of a virtual reality transrectal ultrasound guided prostatic biopsy simulator

We present the design, reliability, face, content and construct validity testing of a virtual reality simulator for transrectal ultrasound (TRUS), which allows doctors-in-training to perform multiple different biopsy schemes. This biopsy system design uses a regular "end-firing" TRUS probe. Movements of the probe are tracked with a micro-magnetic sensor to dynamically slice through a phantom patient's 3D prostate volume to provide real-time continuous TRUS views. 3D TRUS scans during prostate biopsy clinics were recorded. Intrinsic reliability was assessed by comparing the left side of the prostate to the right side of the prostate for each biopsy. A content and face validity questionnaire was administered to 26 doctors to assess the simulator. Construct validity was assessed by comparing notes from experts and novices with regards to the time taken and the accuracy of each biopsy. Imaging data from 50 patients were integrated into the simulator. The completed VR TRUS simulator uses real patient images, and is able to provide simulation for 50 cases, with a haptic interface that uses a standard TRUS probe and biopsy needle. Intrinsic reliability was successfully demonstrated by comparing results from the left and right sides of the prostate. Face and content validity respondents noted the realism of the simulator, and its appropriateness as a teaching model. The simulator was able to distinguish between experts and novices during construct validity testing. A virtual reality TRUS simulator has successfully been created. It has promising face, content and construct validity results.

Physics Contributions Effect of using different U/S probe Standoff materials in image geometry for interventional procedures: the example of prostate

PurposeThis study investigates the distortion of geometry of catheters and anatomy in acquired U/S images, caused by utilizing various stand-off materials for covering a transrectal bi-planar ultrasound probe in HDR and LDR prostate brachytherapy, biopsy and other interventional procedures. Furthermore, an evaluation of currently established water-bath based quality assurance (QA) procedures is presented.Material and methodsImage acquisitions of an ultrasound QA setup were carried out at 5 MHz and 7 MHz. The U/S probe was covered by EA 4015 Silicone Standoff kit, or UA0059 Endocavity balloon filled either with water or one of the following: 40 ml of Endosgel®, Instillagel®, Ultraschall gel or Space OAR™ gel. The differences between images were recorded. Consequently, the dosimetric impact of the observed image distortion was investigated, using a tissue equivalent ultrasound prostate phantom – Model number 053 (CIRS Inc., Norfolk, VA, USA).ResultsBy using the EA 4015 Silicone Standoff kit in normal water with sound speed of 1525 m/s, a 3 mm needle shift was observed. The expansion of objects appeared in radial direction. The shift deforms also the PTV (prostate in our case) and other organs at risk (OARs) in the same way leading to overestimation of volume and underestimation of the dose. On the other hand, Instillagel® and Space OAR™ “shrinks” objects in an ultrasound image for 0.65 mm and 0.40 mm, respectively.ConclusionsThe use of EA 4015 Silicone Standoff kit for image acquisition, leads to erroneous contouring of PTV and OARs and reconstruction and placement of catheters, which results to incorrect dose calculation during prostate brachytherapy. Moreover, the reliability of QA procedures lies mostly in the right temperature of the water used for accurate simulation of real conditions of transrectal ultrasound imaging.

Documenting the location of systematic transrectal ultrasound-guided prostate biopsies: correlation with multi-parametric MRI.

During transrectal ultrasound (TRUS)-guided prostate biopsies, the actual location of the biopsy site is rarely documented. Here, we demonstrate the capability of TRUS-magnetic resonance imaging (MRI) image fusion to document the biopsy site and correlate biopsy results with multi-parametric MRI findings. Fifty consecutive patients (median age 61 years) with a median prostate-specific antigen (PSA) level of 5.8 ng/ml underwent 12-core TRUS-guided biopsy of the prostate. Pre-procedural T2-weighted magnetic resonance images were fused to TRUS. A disposable needle guide with miniature tracking sensors was attached to the TRUS probe to enable fusion with MRI. Real-time TRUS images during biopsy and the corresponding tracking information were recorded. Each biopsy site was superimposed onto the MRI. Each biopsy site was classified as positive or negative for cancer based on the results of each MRI sequence. Sensitivity, specificity, and receiver operating curve (ROC) area under the curve (AUC) values were calculated for multi-parametric MRI. Gleason scores for each multi-parametric MRI pattern were also evaluated. Six hundred and 5 systemic biopsy cores were analyzed in 50 patients, of whom 20 patients had 56 positive cores. MRI identified 34 of 56 positive cores. Overall, sensitivity, specificity, and ROC area values for multi-parametric MRI were 0.607, 0.727, 0.667, respectively. TRUS-MRI fusion after biopsy can be used to document the location of each biopsy site, which can then be correlated with MRI findings. Based on correlation with tracked biopsies, T2-weighted MRI and apparent diffusion coefficient maps derived from diffusion-weighted MRI are the most sensitive sequences, whereas the addition of delayed contrast enhancement MRI and three-dimensional magnetic resonance spectroscopy demonstrated higher specificity consistent with results obtained using radical prostatectomy specimens.

Documenting the location of prostate biopsies with image fusion.

OBJECTIVE To develop a system that documents the location of transrectal ultrasonography (TRUS)-guided prostate biopsies by fusing them to MRI scans obtained prior to biopsy, as the actual location of prostate biopsies is rarely known. PATIENTS AND METHODS Fifty patients (median age 61) with a median prostate-specific antigen (PSA) of 5.8 ng/ml underwent 3T endorectal coil MRI prior to biopsy. 3D TRUS images were obtained just prior to standard TRUS-guided 12-core sextant biopsies wherein an electromagnetic positioning device was attached to the needle guide and TRUS probe in order to track the position of each needle pass. The 3D-TRUS image documenting the location of each biopsy was fused electronically to the T2-weighted MRI. Each biopsy needle track was marked on the TRUS images and these were then transposed onto the MRI. Each biopsy site was classified pathologically as positive or negative for cancer and the Gleason score was determined. RESULTS The location of all (n= 605) needle biopsy tracks was successfully documented on the T2-weighted (T2W) MRI. Among 50 patients, 20 had 56 positive cores. At the sites of biopsy, T2W signal was considered 'positive' for cancer (i.e. low in signal intensity) in 34 of 56 sites. CONCLUSION It is feasible to document the location of TRUS-guided prostate biopsies on pre-procedure MRI by fusing the pre-procedure TRUS to an endorectal coil MRI using electromagnetic needle tracking. This procedure may be useful in documenting the location of prior biopsies, improving quality control and thereby avoiding under-sampling of the prostate as well as directing subsequent biopsies to regions of the prostate not previously sampled.

Fluorescence time-resolved imaging system embedded in an ultrasound prostate probe

Ultrasound imaging (US) of the prostate has a low specificity to distinguish tumors from the surrounding tissues. This limitation leads to systematic biopsies. Fluorescent diffuse optical imaging may represent an innovative approach to guide biopsies to tumors marked with high specificity contrast agents and therefore enable an early detection of prostate cancer. This article describes a time-resolved optical system embedded in a transrectal US probe, as well as the fluorescence reconstruction method and its performance. Optical measurements were performed using a pulsed laser, optical fibers and a time-resolved detection system. A novel fast reconstruction method was derived and used to locate a 45 µL ICG fluorescent inclusion at a concentration of 10 µM, in a liquid prostate phantom. Very high location accuracy (0.15 cm) was achieved after reconstruction, for different positions of the inclusion, in the three directions of space. The repeatability, tested with ten sequential measurements, was of the same order of magnitude. Influence of the input parameters (optical properties and lifetime) is presented. These results confirm the feasibility of using optical imaging for prostate guided biopsies.

MR to ultrasound registration for image-guided prostate interventions

A deformable registration method is described that enables automatic alignment of magnetic resonance (MR) and 3D transrectal ultrasound (TRUS) images of the prostate gland. The method employs a novel "model-to-image" registration approach in which a deformable model of the gland surface, derived from an MR image, is registered automatically to a TRUS volume by maximising the likelihood of a particular model shape given a voxel-intensity-based feature that represents an estimate of surface normal vectors at the boundary of the gland. The deformation of the surface model is constrained by a patient-specific statistical model of gland deformation, which is trained using data provided by biomechanical simulations. Each simulation predicts the motion of a volumetric finite element mesh due to the random placement of a TRUS probe in the rectum. The use of biomechanical modelling in this way also allows a dense displacement field to be calculated within the prostate, which is then used to non-rigidly warp the MR image to match the TRUS image. Using data acquired from eight patients, and anatomical landmarks to quantify the registration accuracy, the median final RMS target registration error after performing 100 MR-TRUS registrations for each patient was 2.40 mm.

Ultrasound-guided X-ray free percutaneous nephrolithotomy for treatment of simple stones in the flank position

The purpose of this study was to examine the effectiveness and safety of percutaneous nephrolithotomy with ultrasonography-guided renal access in the flank position without the use of fluoroscopy in any stage of the procedure. Percutaneous nephrolithotomy was performed in flank position under the guidance of ultrasound (USG) without the use of fluoroscopy between December 2008 and January 2010 on 43 patients who had kidney stones bigger than 20mm. Access to the kidney's proper calyx was achieved by dilatation through the guide wire placed after insertion of the needle through the needle director under the guidance of transrectal ultrasound probe placed on the patient's flank area. A convex USG probe was used for imaging during dilatation and lithotripsy instead of fluoroscopy. Access to the targeted calyx was achieved successfully in all patients (100%). The percentage stone free rate was 86.1% (37 patients). Residual stones were detected in six patients. Their dimensions ranged from 5 to 12mm. The mean stone diameter was 29 (20-41) mm, duration of surgery was 87.1±43.2 (55-210)min and duration of hospital stay was 3.1 (2-8) days. Blood transfusions were given to two patients; none of the patients had major intraoperative or postoperative complications. In comparison with standard percutaneous nephrolithotomy, percutaneous nephrolithotomy in flank position under ultrasonographic imaging instead of using fluoroscopy seems to be safe and effective. This procedure has to be limited to selected cases with one or maximum two big stones in the pelvis or in a single calyx in absence of complex intrarenal anatomy. Both surgical team and the patients were protected from the harmful effects of radiation. Regarding anesthesia, flank position is more comfortable for the patient than prone position.

Tandem-robot Assisted Laparoscopic Radical Prostatectomy to Improve the Neurovascular Bundle Visualization: A Feasibility Study

To examine the feasibility of image-guided navigation using transrectal ultrasound (TRUS) to visualize the neurovascular bundle (NVB) during robot-assisted laparoscopic radical prostatectomy (RALP). The preservation of the NVB during radical prostatectomy improves the postoperative recovery of sexual potency. The accompanying blood vessels in the NVB can serve as a macroscopic landmark to localize the microscopic cavernous nerves in the NVB. A novel, robotic transrectal ultrasound probe manipulator (TRUS Robot) and three-dimensional (3-D) reconstruction software were developed and used concurrently with the daVinci surgical robot (Intuitive Surgical, Inc., Sunnyvale, CA) in a tandem-robot assisted laparoscopic radical prostatectomy (T-RALP). After appropriate approval and informed consent were obtained, 3 subjects underwent T-RALP without associated complications. The TRUS Robot allowed a steady handling and remote manipulation of the TRUS probe during T-RALP. It also tracked the TRUS probe position accurately and allowed 3-D image reconstruction of the prostate and surrounding structures. Image navigation was performed by observing the tips of the daVinci surgical instruments in the live TRUS image. Blood vessels in the NVB were visualized using Doppler ultrasound. Intraoperative 3-D image-guided navigation in T-RALP is feasible. The use of TRUS during radical prostatectomy can potentially improve the visualization and preservation of the NVB. Further studies are needed to assess the clinical benefit of T-RALP.

A comparison of the accuracy of statistical models of prostate motion trained using data from biomechanical simulations

Statistical shape models (SSM) are widely used in medical image analysis to represent variability in organ shape. However, representing subject-specific soft-tissue motion using this technique is problematic for applications where imaging organ changes in an individual is not possible or impractical. One solution is to synthesise training data by using biomechanical modelling. However, for many clinical applications, generating a biomechanical model of the organ(s) of interest is a non-trivial task that requires a significant amount of user-interaction to segment an image and create a finite element mesh. In this study, we investigate the impact of reducing the effort required to generate SSMs and the accuracy with which such models can predict tissue displacements within the prostate gland due to transrectal ultrasound probe pressure. In this approach, the finite element mesh is based on a simplified geometric representation of the organs. For example, the pelvic bone is represented by planar surfaces, or the number of distinct tissue compartments is reduced. Such representations are much easier to generate from images than a geometrically accurate mesh. The difference in the median root-mean-square displacement error between different SSMs of prostate was <0.2 mm. We conclude that reducing the geometric complexity of the training model in this way made little difference to the absolute accuracy of SSMs to recover tissue displacements. The implication is that SSMs of organ motion based on simulated training data may be generated using simplified geometric representations, which are much more compatible with the time constraints of clinical workflows.

Sensitivity study of an ultrasound coupled transrectal electrical impedance tomography system for prostate imaging

In 2009, prostate cancer ranked as the most common cancer and the second most fatal cancer in men in the United States. Unfortunately, the current clinical diagnostic methods (e.g. prostate-specific antigen (PSA), digital rectal examination, endorectal MRI, transrectal ultrasound, biopsy) used for detecting and staging prostate cancer are limited. It has been shown that cancerous prostate tissue has significantly different electrical properties when compared to benign tissues. Based on these electrical property findings, a transrectal electrical impedance tomography (TREIT) system is proposed as a novel prostate imaging modality. The TREIT system comprises an array of electrodes interfaced with a clinical transrectal ultrasound (TRUS) probe. We evaluate this imaging system through a series of phantom imaging experiments to assess the system's ability to image high and low contrast objects at various positions. We found that the TREIT system can easily discern high contrast inclusions of 1 cm in diameter at distances centered at two times the radius of the TREIT probe away from the probe surface. Furthermore, this technology's ability to detect low contrast inclusions suggests that it has the potential to successfully detect prostate cancer.

Visual pain score during transrectal ultrasound-guided prostate biopsy using no anaesthesia or three different types of local anaesthetic application

To evaluate the pain score during transrectal ultrasound (TRUS)-guided prostate biopsy using three different anaesthetic applications and no anaesthesia. One-hundred men undergoing TRUS-guided prostate biopsy were prospectively enrolled in this study. Patients were randomized to four groups. Group 1 (n = 25) received no anaesthesia, group 2 (n = 25) was administered a perianal lidocaine injection, group 3 (n = 25) was administered a periprostatic lidocaine injection, and group 4 (n = 25) was administered a combination of perianal-intrarectal lidocaine-prilocaine cream. The anaesthetic application was given 5 min before the procedure. All patients were asked to indicate the level of pain experienced on a visual analogue scale (VAS) during three situations, including when the TRUS probe was inserted and 15 min and 2 weeks after biopsy. Mean pain scores were similar in all groups at the time of probe insertion. Mean pain scores showed statistically significant differences between group 1 and the other groups, except for group 4, 15 min after the procedure. Group 3 showed better pain control 15 min after biopsy and this difference was statistically significant (p < 0.043).The VAS scores were similar 2 weeks after the procedure in all groups. Anaesthetic application before TRUS-guided prostate biopsy may be advocated. The application of periprostatic lidocaine seems to be the most advantageous method for lowering the perception of pain.

Sensitivity study of an ultrasound coupled transrectal electrical Impedance Tomography system for prostate imaging

In 2009, prostate cancer ranks as the most common cancer and the second most fatal cancer in men in the United States. Unfortunately, the current clinical diagnostic methods (e.g. prostate-specific antigen (PSA), digital rectal examination, endorectal MRI, transrectal ultrasound, biopsy) used for detecting and staging prostate cancer are limited. It has been shown that cancerous prostate tissue has significantly different electrical properties when compared to benign tissues. Based on these electrical property findings, a TransRectal Electrical Impedance Tomography (TREIT) system is proposed as a novel prostate imaging modality. The TREIT system is comprised of an array of electrodes interfaced with a clinical TransRectal UltraSound (TRUS) probe. We evaluate this imaging system through series of phantom imaging experiments to assess the system's ability to image high and low contrast objects at various positions. We found that the TREIT system can easily discern high contrast inclusions of 1 cm in diameter at distances centered at 2 times the radius of the TREIT probe away from the probe surface. Furthermore, this technology's ability to detect low contrast inclusions suggests that it has the potential to successfully detect prostate cancer.

926 SYSTEMATIC ANALYSIS OF SATURATION BIOPSY WITH 20 PERIPHERAL CORES AND 4 CORES FROM THE TRANSITION ZONE BASED ON 62 REDUCED BIOPSY SCHEMES AFTER AT LEAST ONE NEGATIVE BIOPSY

You have accessJournal of UrologyProstate Cancer: Localized IV1 Apr 2010926 SYSTEMATIC ANALYSIS OF SATURATION BIOPSY WITH 20 PERIPHERAL CORES AND 4 CORES FROM THE TRANSITION ZONE BASED ON 62 REDUCED BIOPSY SCHEMES AFTER AT LEAST ONE NEGATIVE BIOPSY Marco Auprich, Stefan Gutschi, Günter Gallè, Martin Pichler, Sebastian Mannweiler, Karl Pummer, and Herbert Augustin Marco AuprichMarco Auprich More articles by this author , Stefan GutschiStefan Gutschi More articles by this author , Günter GallèGünter Gallè More articles by this author , Martin PichlerMartin Pichler More articles by this author , Sebastian MannweilerSebastian Mannweiler More articles by this author , Karl PummerKarl Pummer More articles by this author , and Herbert AugustinHerbert Augustin More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1742AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES According to the recommendations of the European Association of Urology (EAU) a prostate biopsy with at least 10 cores should be performed after an initial negative biopsy. To find the optimal number and location of cores to be sampled during a repeat biopsy in an extended setting, we systematically analyzed a saturation scheme with 20 lateral and 4 transitional cores, performed after at least one prior biopsy. METHODS Clinical and biopsy data were evaluated from 302 patients who underwent repeat biopsies due to persisting or rising prostate-specific antigen (PSA) values (≥2.5-10 ng/ml), suspicious digital rectal examination (DRE) and/or suspicious findings in previous biopsies. Saturation biopsies were performed under sedoanalgesia by three physicians with a biplanar transrectal ultrasound probe and an 18-Gauge biopsy gun (Bard) following a strict topographical scheme. All biopsy samples were evaluated by the same-pathologist (S.M.). The reduction of detection rate was calculated bei McNemar test and Spearman's rho was performed to correlate patient characteristics. RESULTS Biopsy results revealed prostate cancer (PC) in 109 (36.1%) patients and of these, 44 (40.4%) showed Gleason scores ≥7. In 8 (7.3%) patients PC was detected only in the transitional zone. By univariate and multivariate analyses, age, total PSA level and prostate volume were significant predictors (p≤0.01). Analysis of the single cores indicated PC most frequently in the left lateral area and the right transition zone and least often in the basal areas. Systematic analysis of 62 different biopsy schemes with decreasing core numbers found a significant (p<0.031) reduction in PC detection for each reduction in core number except for two 20 biopsy schemes with 16 lateral and 4 transitional cores. CONCLUSIONS Our study shows, that each reduction in the number of biopsy cores taken, decreases the detection rate of PC. Therefore, a saturation biopsy scheme using at least 20 cores should be performed after an initial negative biopsy. If no cores have previously been taken from the transition zone, this region should be included in the following biopsy. Graz, Austria© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e361 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Marco Auprich More articles by this author Stefan Gutschi More articles by this author Günter Gallè More articles by this author Martin Pichler More articles by this author Sebastian Mannweiler More articles by this author Karl Pummer More articles by this author Herbert Augustin More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...